Abrine and Hypaphorine

Abrine (I), the A7tl-methyl derivative of L-tryptophan, occurs in the seeds of the jequirity (Abrus precatorius L.) (12, 13) so far it has not 

The constitution of abrine was proved by methylation with methyl iodide and methanolic sodium hydroxide, which gave the same methyl ester methiodide as did similar treatment of L-tryptophan (15). Since the product was almost completely racemized (16), this did not establish the configuration of the asymmetric center. The configurational identity of abrine and L-tryptophan was proved by Cahill and Jackson (16), who obtained the same optically pure methyl betaine (II) from both abrine and L-tryptophan by methylation with methyl iodide and methanolic sodium hydroxide. Under the appropriate conditions, the racemic methyl ester methiodide crystallized out, and was removed the methyl bfetaine (II) which remained unesterified also escaped racemization, and was recovered from the mother liquors. 

The natural occurrence of hypaphorine is probably not confined to Erythrina species. Von Lippmann (29) isolated from beet shoots a substance with the appropriate physical and analytical properties which, 

The decomposition of hypaphorine into indole and trimethylamine occurs slowly in the rotting wood of Abrus precatorius L., and is responsible for its fecal odor. It also led van Romburgh (30) to propose the correct structure for hypaphorine, which was soon established by synthesis from L-tryptophan (17). 

The methyl ester of iVb-dimethyl-L-tryptophan (Ha) also occurs naturally, and has recently been shown to be the major base oiPultenaea altissima P. Muell. ex Benth. (Leguminosae) (30a). 

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